Fidel Castro has made a rare public appearance at his 90th birthday gala - rubbishing rumours that he had died.

The leader of the 1959 revolution thanked fellow Cubans for their well wishes and lambasted his old foe the United States in a column carried by state-run media.

Cuba went into overdrive this month honouring the retired "El Comandante," who built a state on the doorstep of the United States, surviving what it says were hundreds of assassination attempts along the way.

Thousands danced to Latin beats along Havana's curving seafront Malecon boulevard throughout the night from Friday to Saturday.

At the giant street party, a live band played "Happy Birthday" on the stroke of midnight and fireworks exploded on the other side of the bay.

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Former Cuban President Fidel Castro, sitting next to Venezuelan President Nicolas Maduro is seen attending the celebration of his 90th birthday (Image: AFP PHOTO/CUBADEBATE.CU)

Former Cuban President Fidel Castro, Venezuelan President Nicolas Maduro and Cuban President Raul Castro are seen attending the celebration (Image: AFP PHOTO/CUBAVISION)

The iconic leftist revolutionary, who handed over power in 2008 to his younger brother Raul due to ill health, appeared later in the day for a birthday gala featuring children's theater, live music and videos from his life.

Seated in the front row of the Karl Marx theater, he was flanked by Raul and regional ally Venezuelan President Nicolas Maduro.

Increasingly frail, Castro had last made an official appearance at the Communist Party Congress in April.

Castro greets a girl during the celebration of his 90th birthday (Image: MARCELO GARCIA/AFP/Getty Images)

"I see him as animated. He was speaking with everyone. I was very happy; he seemed very happy, especially because recently they haven't put him on television because he's been sick but now he seems much better," said Cuban youth, Lenet de la Caridad.

Fidel Castro appeared at his brithday celebrations amid rumours that he had died (Image: Miraflores Palace/Handout via REUTERS)

He still holds a special place for many Cubans.

"In spite of his age, 90 years old. He looks good. Good with his reflections, his way of being, his measured way. His charisma. Truly admirable," said Cuban woman, Haydee Mendez.

Many Cubans feel Fidel is no longer in step with the times. Raul's most broadly feted accomplishment since taking power has been implementing a detente with the United States after a half century of confrontation.

Considered more pragmatic, the younger Castro also introduced market-style reforms to the state-dominated economy and increased personal freedoms, such as the right to travel abroad. Fidel has lent these policies only lukewarm support in public.

But many Cubans still revere Fidel for freeing Cuba from U.S. domination and introducing universal, free healthcare and education.